Is there any information on how the files work in Octoprint? I am a new user and when I installed it, it seems to have read the files on my inserted SD card, though the names are so shortened, I can't tell what they are.
So, I have two basic questions. Is there any way to change how the names are displayed, especially those it read from the SD card?
More basic question, when I upload files from my computer, where does Octoprint store them? Are they in a chip in the raspberry pi, or on the SD card?
Not easily. This is very dependent on how the printer's firmware sends out the filenames. If you check the terminal tab as you connect to the printer you will probably see this communication happen to read the files. You'd need your printer firmware to support the long file names first.
If you just select 'upload', then they are stored on the micro SD card you put the OS on, usually called 'locally' since they are on the same device as OctoPrint itself. If you select 'upload to SD' then they would end up on the SD card on your printer. Once you get using OctoPrint you'll probably never need to use this. Be aware as well that transferring the file through OctoPrint can be quite slow.
I just want to add that the slow transfer isn't Octoprints fault - it's because of the slow connection to the printer.
Most of the time it uses a baudrate of 115200.